How does Arch know when to switch between graphics cards?

ljwagerfield · 2013-08-22 10:22:32

My MB Pro has an integrated Intel GPU and dedicated Nvidia graphics card. It also seems to run very hot when playing back video.

How does Arch know when to switch between the two, say, when playing back video? Should I be concerned that Arch might always be using one or the other, and not switching correctly?

donniezazen · 2013-08-22 18:23:36

It doesn't. Use Bumblebee to manually manage dedicated GPU.

ljwagerfield · 2013-08-23 14:09:27

Thank you!

What is the default behavior? I've noticed Arch picks up both displays when I run lspci (Nouveau and Intel) so which is it using currently? How can I tell?

lifeafter2am · 2013-08-23 14:11:57

ljwagerfield wrote:

Thank you!
What is the default behavior? I've noticed Arch picks up both displays when I run lspci (Nouveau and Intel) so which is it using currently? How can I tell?

https://wiki.archlinux.org/index.php/Bu … management

ljwagerfield · 2013-08-26 10:38:23

Apologies, I meant:

Without any additional software/packages, what is the default behavior used by Arch? As I understand, the IGP is always on, whereas the DGP is only switched on when higher processing performance is required.

Does this mean Arch renders, by default, everything to the IGP?

donniezazen · 2013-08-27 03:03:09

Both cards will always be on unless you install bumblebee or other scripts to turn of one of the graphic cards. I am not 100% sure but I think Arch will use the graphic card that you installed drivers of during installation. Even with bumblebee installed your system can't decide what is a higher-processing-graphic-task and it has no way of switching graphic cards consequently everything is routed to integrated card. That's why your use optirun command to enable dedicated card for specific processes.

Lekensteyn · 2013-08-27 10:22:14

Correction: Arch will use the Intel graphics card. Even if you install drivers for the nvidia card, it won't be used by default.

Cthulhu82 · 2013-08-28 20:02:02

Lekensteyn wrote:

Correction: Arch will use the Intel graphics card. Even if you install drivers for the nvidia card, it won't be used by default.

But the Nvidia card will still be power up and consuming energy for nothing, unless you install bumblebee + bbswitch.
Then the Nvidia card will be on only when you use it, but this isn't automatic : you need to specificaly launch an application with bumblebee for that (see the links above to the wiki for detail).
However, the last nvidia drivers bring a true optimus support, but it is still an early thing, unstable (when bumblebee is very stable now) and complicated to install (look here and here for details).

Arch Linux

#1 2013-08-22 10:22:32

How does Arch know when to switch between graphics cards?

#2 2013-08-22 18:23:36

Re: How does Arch know when to switch between graphics cards?

#3 2013-08-23 14:09:27

Re: How does Arch know when to switch between graphics cards?

#4 2013-08-23 14:11:57

Re: How does Arch know when to switch between graphics cards?

#5 2013-08-26 10:38:23

Re: How does Arch know when to switch between graphics cards?

#6 2013-08-27 03:03:09

Re: How does Arch know when to switch between graphics cards?

#7 2013-08-27 10:22:14

Re: How does Arch know when to switch between graphics cards?

#8 2013-08-28 20:02:02

Re: How does Arch know when to switch between graphics cards?

Board footer